One traditional method for curing muscle ache and stiffness is to bathe spa, which can be found near volcanic sites. The molten rock, or lava, issued from a volcano usually emits radiation in the wavelength range of 6-12 .mu.m, which lies in the spectrum of far-infrared. The spa is fed by underground water heated by the lava, so it also contains the far-infrared radiation. The spa is very effective in curing muscle ache and stiffness but it is also a costly method.
In addition to the spa, many surgical tapes are available for use in curing muscle ache and stiffness. These surgical tapes can be adhered conveniently and easily to the skin.
However, one drawback of the prior art surgical tapes is that they use medicines that may cause environmental pollution when discarded after use. Another drawback is that these surgical tapes often have a limited period of effectiveness.
A medical research paper entitled "The Effects of Porcelain-emitted Far-infrared Radiation on the Vitalization of Lymphocyte" and disclosed by a Japanese research center has proven that far-infrared radiation can vitalize human cells. In the research, it is found that several kinds of porcelain emit far-infrared radiation when heated. The radiation affects the human body in several aspects. For example, it raises the temperature in the inner layer of the skin, expands the capillaries, ameliorates blood circulation, promotes metabolism, relaxes the sensory nerves, and regulates the autonomic nerve system.
Through research on far-infrared emitting porcelains, the inventor has found that a compound made from one kind of volcanic rock called perlite can be used to cure muscle ache and stiffness. The perlite rock is powdered and sintered at 1100.degree.-1300.degree. C. and then mixed with at least one metallic oxide of which the metal is selected from the group consisting of Ta, Nb, Pd, Ni, Ge, Ti and Zr of specific proportions. When layered on a tape and adhered to the muscle, this compound can emit far-infrared radiation when it comes in contact with the body heat. The amount of radiation can expand the capillaries 1.3 to 1.4 time.